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Phytochemical study of Pittosporum undulatum: Searching for new guaiane-type sesquiterpenes with anti-inflammatory activity

2014; Thieme Medical Publishers (Germany); Volume: 80; Issue: 16 Linguagem: Inglês

10.1055/s-0034-1394711

1439-0221

Sofia Alexandra Carreiro Mendes, João Madruga, Edeltrudes de Oliveira Lima, MJU Ferreira,

Phytochemical Studies and Bioactivities

Pittosporum undulatum Ventenant (Pittosporaceae) is a highly invasive weed that often outcompetes other plants. Nevertheless, its fruits have become a traditional anti-inflammatory medicine in Azores Archipelago. The Azores ethnobotany refers the use of an infusion in alcohol or vinegar of P. undulatum fruits due to their anti-inflammatory activity. Therefore, taking into account the anti-inflammatory activity of other species of the genus Pittosporum [1], a preliminary study was performed in order to find new anti-inflammatory compounds [2], after identification of the plant material by a taxonomist. Bioassay-guided fractionation of the methanol extract of P. undulatum fruits, analyzing the inhibitory effects on chemical mediators released by the LPS activated RAW 264.7 murine macrophages cell line, yielded two unprecedented guaiane-type sesquiterpene glycosides (undulatumosides A and B) along with six known compounds, including the guaiane isomers 5-guaien-11-ol and 4-guaien-11-ol. When evaluating the inflammatory activity of the guaianes, undulatumoside A, 5-guaien-11-ol and 4-guaien-11-ol displayed IC50 values of 16.4, 8.1 and 7.2µM, respectively, comparable to that of the positive control, indomethacin (IC50= 18.2µM) [2]. Aiming to find out new compounds with anti-inflammatory activity from P. undulatum, further phytochemical studies of the methanol extract of P. undulatum fruits gave rise to the isolation of five new guaiane-type sesquiterpenes including two glucosides secoguaianes. Their structures were assigned based on spectroscopic methods namely 1D-NMR (1H, 13C, DEPT) and 2D-NMR (COSY, HMBC, HMQC) experiments.